Am I reading my psu numbers correctly? (pic included)

[sputtering]

I've been trying to teach myself about the various parts of computers, and I'm somewhat unsure when it comes to psu's. The one I have is rated at 300w:



So first off, the 3.3v and 5v = 130w, if I understand, is something that I likely won't need to concern myself with.

For the 12v rails, the stated amps translate to 96w and 168w, for a total of 264w. So that's what the cpu, gpu and any other demanding components may use. It only matters what they equal when combined, not necessarily what they amount to individually?

Then if the 12v's were maxed out, that would only leave 36w for everything else to run off of. (And lead to a burned out power supply I presume.)

But then, I've seen psu's that claim to be 300w with, say, 19 total amps as opposed to my 22. So then that would come to 228w on the 12v. So would that mean that the two psu's, despite having the same wattage, would effectively have different overall capabilities?

I'm sure I'm likely missing something important, but am I at least on the right track?

 

[toyftw]

I've been trying to teach myself about the various parts of computers, and I'm somewhat unsure when it comes to psu's. The one I have is rated at 300w:



So first off, the 3.3v and 5v = 130w, if I understand, is something that I likely won't need to concern myself with.

For the 12v rails, the stated amps translate to 96w and 168w, for a total of 264w. So that's what the cpu, gpu and any other demanding components may use. It only matters what they equal when combined, not necessarily what they amount to individually?

Then if the 12v's were maxed out, that would only leave 36w for everything else to run off of. (And lead to a burned out power supply I presume.)

But then, I've seen psu's that claim to be 300w with, say, 19 total amps as opposed to my 22. So then that would come to 228w on the 12v. So would that mean that the two psu's, despite having the same wattage, would effectively have different overall capabilities?

I'm sure I'm likely missing something important, but am I at least on the right track?

Hi - Yes you are on the right track and understand the dynamics fairly well. The key spec
is the +12v rail's avail amps. That exact model # isn't in realhardtechx's PSU database, but generally when
there is more than one +12v rail, the total amps avail is less than the sum of the two.

The one FSP 300-60 I found with a 14 + 8 amps on the +12v rails does in fact have all 22 available.

If you have documentation on the PSU check & see what protection features are included with the PSU,
so if you do max out and attempt to draw more power than it can deliver it will shut down as opposed to burning up.

I couldn't find a trusted review of it, so I don't know what protection features this PSU has and FSP doesn't list them
on their site for this model #.

Plz be aware that if you add or plan to add a mid range GPU to your PC, this PSU is not sufficient. Almost
all systems with mid range & above GPU's require more than 22 +12v amps. That PSU would power a
system with an hd7750. Anything more powerful would require a PSU upgrade.

 

[sputtering]

Okay, cool. I'm glad I can at least say I have some idea of what I'm doing, unlike the first time I upgraded my computer several years ago. Good ol' 8500gt...that card served me well.

There's one more question I have that came up while doing further research after posting here. I came across some specs where the 12v had a higher capacity than what the psu was rated for. Would that potentially be from one of those off brands that people warn about, or does it even matter?

 

[toyftw]

Okay, cool. I'm glad I can at least say I have some idea of what I'm doing, unlike the first time I upgraded my computer several years ago. Good ol' 8500gt...that card served me well.

There's one more question I have that came up while doing further research after posting here. I came across some specs where the 12v had a higher capacity than what the psu was rated for. Would that potentially be from one of those off brands that people warn about, or does it even matter?

Hi again - Yeah, I'd say that has to be an off brand. A quality supplier or Mfg wouldn't allow such a mis-statement.
I would say it does matter because if they are so inept as to quote a higher individual (+12v) amperage, then
it is most likely they have made errors or compromised quality in the manufacturing.

 

[sputtering]

Thanks for the help. I don't foresee a psu upgrade in the near future, so this will help with my decision making until then. Plus I like learning new things.